perlio.c, PerlIO_tmpfile: Fall back to cwd if we have no /tmp or TMPDIR
ext/POSIX/t/time.t: Conditionalize the use of setlocale/LC_TIME

On Android, all locales are simply disabled, which broke the assumption
that LC_TIME is always available.
ext/POSIX/t/sysconf.t: Skip testing pathconf with _PC_LINK_MAX on android
cpan/Sys-Syslog/Syslog.pm: Conditionalize the use of setlocale/LC_TIME
Android hints: Detect stub functions and mark them as undefined.

Bionic implements several functions as stumps that simply warn
and return null, which leads to situations like this:

FIX ME! implement getprotobyname() bionic/libc/bionic/stubs.c:378

This commit introduces some probes for functions (getnetbyname,
getnetbyaddr, getmntent, getprotobyname, getprotobynumber, endpwent,
ttyname) that we use and are actually stubs in at least some
versions of Android.
If we find a stub, we pretend that the function is undefined, so
the above example becomes this:

Unsupported socket function "getprotobyname" called at -e line 1.

Note that this commit does not fix the modules that assume that
these functions are always available, so 'make test' still fails.
IO::Socket::INET: Handle getprotobyn{ame,umber} not being available
Net::Ping: Handle getprotobyn{ame,umber} not being available
ext/File-Glob/t/basic.t: On android, remove .stdout files from glob()'s results
time64.h: Declare tm_zone as const under Android, but not if using C++
Configure: Minor tweak to allow cross-compiling with g++
MakeMaker: Groundwork for d_libname_unique

Android's linker has some unusual behavior, in that it only uses
the basename of a library in its cache.  That means that, as far as
dlopen() is concerned, the libraries for Hash::Util and List::Util,
both of which are called Util.so, are the same.

This commit teaches ExtUtils::MM_Unix about d_libname_unique.  When
defined, it signals MakeMaker to rename the .so files to something
"unique" -- so for example, Hash/Util/Util.so becomes
Hash/Util/Perl_Hash_Util.so.
Teach XSLoader about d_libname_unique
Teach DynaLoader about d_libname_unique
android hints: Always define d_libname_unique
t/op/getpid.t: Silence undef warnings if getconf doesn't exist.

If a platform has getppid() but not getconf and we're building a
threaded perl, this file would've shown undef warnings, although
no tests were affected.
pod/perlport.pod: Note which functions are not available on Android
t/op/threads-dirh.t: Only test telldir and seekdir if they are available
doio.c: Two variables only need to be available if -DUSE_SHELL_ALWAYS is not true
sv.c, Perl_dirp_dup: Skip the fchdir sections if telldir and seekdir are not defined
hints/linux-androideabi.sh: getservent_r() is a partial stub, mark it as undefined to avoid issues with threads